Broadband IP Education metropolitan Area network strategy based on BGP/MPLS VPN

Absrtact: Broadband IP metropolitan Area network, routing planning and design is the core link. In the beginning of the network, must be integrated planning. According to the construction of the metropolitan area Network, the routing strategy based on Bgp/mpls VPN is adopted, which is proved to be feasible by practice.

Key words: BGP MPLS VPN IP Routing strategy

1 Broadband metropolitan Area Network overview

A city IP education metropolitan Area network architecture in Cisco GSR 12012, two Catalyst 6509 respectively as the cernet and chinanet of the node, the use of DPT dual-loop broadband (5G) backbone transmission technology. For the city's more than 2000 educational institutions, schools and the vast number of social users to provide broadband application services and Internet access services, but also IP telephony and other services of the carrier network. The project includes metropolitan backbone network and user access network two parts, backbone network includes 4 core nodes, a number of convergence nodes, the user access network (that is, the resident network) mainly provide Ethernet, Cable Modem, ADSL, Wireless broadband and other access methods. The net has two exits: cernet export, chinanet export. The two exits are located at two core nodes, providing business diversion, resolving the problem of chinanet and cernet mutual access, and providing export backup for cernet users.

Broadband IP metropolitan Area Network construction is a system engineering, in the planning, design, construction process, must be based on reality, focus on the future, the overall consideration, especially IP routing strategy can not be defective, otherwise it will be in the actual operation of the dilemma, the future development of hidden dangers.

2 Access user needs analysis

There are three main types of access users in this network: Education network users, ordinary access users, composite users (in the entire network has its own exclusive VPN, at the same time have a single interface through the metropolitan area Internet Internet).

Education Network user refers to some tertiary institutions, educational institutions and primary and secondary schools, denoted for cernet users. Most of them can apply for multiple C-class legal addresses, because the campus network will have a large number of home page connections, some users may be due to the public address is not enough to use private address. Such users can directly access cernet resources without address translation, and cernet users require direct access to those users. In order to distinguish the two kinds of users of cernet, the cernet referred to as the internal cernet, the address is the legal address of cernet, and the cernet which does not belong to this net is called external cernet.

Ordinary access user refers to enterprise users and individual users (mainly chinanet users, denoted 163 users), they do not have the requirements of VPN access, but only on the Internet. In most cases, this type of user cannot apply to a legal address and use a private address.

Because there are chinanet and cernet mutual access are slow, and cernet users to go abroad to pay more and so on issues (if this part of the visit through the chinanet exit, can solve the problem). Therefore, for the common access users, the corresponding routing strategy needs to be developed, when the access to cernet through the cernet export access, when the access to chinanet through the chinanet export access. And when the two network visits, you should consider using NAT/NAPT conversion, the following gives a solution based on Bgp/mpls VPN.

Design and implementation of 3 BGP/MPLS VPN routing strategy

Regarding OSPF routing design, it is recommended that this IGP route be used only to establish the path between the backbone routers to ensure the smooth and reliable channel between the backbone routers. Internet Routing and User routing information is prohibited from adding Is-is routing calculations to ensure backbone stability.

In order to implement MPLS VPN, it is recommended to use MP-BGP as the routing protocol between the PE devices of ISP to distribute VPN routing information in the ISP backbone, and MPLS is used to forward VPN service from one VPN site to another VPN site.

In the Internet with the use of BGP4, if connected with the network, the ISP assigned by the autonomous domain number or the Internet to retain the autonomous domain number; If you are connected to other non-Internet networks, it is recommended that you use the Internet to preserve the autonomous domain number.

3.1 User Type Analysis

(1) Access user type:

Internal ordinary users-------IP address can be assigned to users;

Internal cernet Access User---IP address is not allocated.

(2) Address assignment classification:

Cernet users are all legal addresses;

Address Type I: Some internal ordinary users use the legal address;

Address Type II: All internal ordinary users adopt private addresses.

(3) Access node type:

Class A: Ordinary Access users--------no special address required users;

Class B: Internal cernet----------legal cernet address;

Class C: External 163------------legal chinanet address;

Class D: External cernet----------legal cernet address;

Class E: Ordinary Access user---------have legal chinanet address requirements;

Class F: Normal access user---------have legal cernet address requirements.